Effect of internal migration on inequalities in mortality in Wales: an e-cohort study

• Published in: The Lancet (British edition) 2016-11, Vol.388, p.S50-S50
• Main Authors: Gartner, Andrea, MPH, Farewell, Daniel M, PhD, Greene, Giles, PhD, Trefan, Laszlo, PhD, Paranjothy, Shantini, Prof, Fone, David L, Prof
• Format: Article
• Language: English
• Subjects: Cohort analysis; Internal Medicine; Internal migration; Migration; Public health
• ISSN: 0140-6736; 1474-547X
• DOI: 10.1016/S0140-6736(16)32286-3

Abstract Background Selective migration is a process whereby individuals of poorer health move to areas with poorer health and social characteristics and vice versa, potentially affecting inequalities. Measures of socioeconomic inequalities in mortality or life expectancy are widely used by government and health services to track changes over time but do not consider migration. This study aimed to estimate the effect of migration on the mortality gradient. Methods Data for the entire population of Wales with a general practice registration on Jan 1, 2006, and follow-up for 24 quarters were record-linked by use of individual identifiers to the Office of National Statistics mortality files within the Secure Anonymised Information Linkage databank, a Welsh data linkage centre. Information included moves between lower super output areas (LSOAs) and associated fifths of deprivation (as defined by the Welsh Index of Multiple Deprivation 2008) at each quarter, age, sex, and, if relevant, date of death. Cox regression models were used to estimate the hazard ratios for the mortality gradient associated with area-level deprivation, adjusting for migration as time-varying covariates. Findings 959 622 (30·6%) of 3 136 881 people had moved. 397 883 (34%) of all moves (1 171 361) were to increased and 415 008 (35·4%) to decreased deprivation. People in the most deprived fifth had a higher risk of death than those in the least deprived fifth (hazard ratio 1·57, 95% CI 1·55–1·60; p